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Homegrown: Trimming an Austrian pine

I have an Austrian pine and we trimmed the top to stimulate growth in the fall of 2008. It seemed to stimulate branching of the tree over the summer, but may have added an unsightly dense knot of growth.

My husband then decided to trim off an alternate leader last spring. Unfortunately, cutting the alternate leader left 1/3 of the tree with no limbs at the bottom of the tree.

Is there any hope it will ever have a beautiful shape? Did we overprune this little tree? Should we leave the tree to grow without our interference from now on?

Thank you.

— Barb

Actually, you may be on the right path. The tree may just need a bit of time, proper application and perhaps a better understanding of the tree for things to work themselves out.

When I talk to people about a pine tree that’s a bit misshapen or thin, the first thing I’ll counsel is patience.

All types of trees can sometimes go through an awkward “teenage” phase when some parts grow faster than others or they’ll go through a growth spurt that kind of knocks them out of proportion.

Left alone, the tree will almost always work out those issues and shape up to be a beautiful specimen.

However, we can sometimes apply a bit of strategic pruning to shorten that awkward phase or minimize any shortcomings the tree may develop. I’m not a big fan of shearing on pines, but if you want to try it, it’s very important to time the pruning carefully or you’ll end up with problems.

Each spring, when the new buds break, the shoots elongate and form what we call “candles.”

As time passes, new needles emerge along the shoots; the shoot completes elongating and sets new buds for the next growing season at the branch tip.

These new branches then harden off, changing from somewhat soft, succulent tissue to harder, woody tissue.

The best time to shear is when this elongation is complete, but before the branches fully harden off. The time for this varies a bit from year to year, but around here it’s usually any time from the end of May into the middle of June.

Pruning much earlier or later than this results in smaller buds and spindly, weaker growth in subsequent years.

If you do shear the pine, shear the entire tree, not just a portion or you’ll end up with that flat top you’re seeing.

You’ll want to start to shear it into the shape you desire, that is, prune less at the very top and progressively more as you go down so you re-establish that cone shape.

Be patient about this; it may take several years of progressively pruning the tree to bring it fully to the shape you want.

You might consider using this method on your tree for a year or two to point it in the right direction.

It’s also important to not cut the candles off too much. Taking just a bit off of the tip will help thicken the tree while minimizing that short, dense, bushy growth.

You probably did the right thing taking the alternate leader off. Sometimes a double leader is not a problem in a pine and sometimes it is.

The problem is that you really won’t know for some years which way things will go and if it needs to be removed at that point, you’re really looking at mangling the tree.

I know the tree looks a bit lopsided now, but that should pass. The adjacent branches will grow into that area, filling it out in time.

Concentrate on giving it the best care you can. Water it deeply but infrequently and fertilize it lightly in the spring with a slow-release nitrogen fertilizer.

You should start to see some improvement next summer, which should continue as time passes.